Segwit needs 95% approval from miners(never going to happen) and only solves blocksize issues short term.
Segwit solves it long term because it enables for proper Lightning Network usage, which is the only way to scale to mainstream levels.
Lightning would take at-least 4-5 years to get activated. Also, it's an off-chain solution not on-chain solution which Satoshi advocated for. This means value spilling over from BTC into other more transact-able alternative currencies.
There is no way to do everything on-chain forever. If Satoshi wanted for all operations to be done on-chain so why did he invented block reward halving?
So people advocate that everything should be done on-chain and free, they are more than welcome to start their own service, build mining farm and donate their money.
Block size is a resource and it sooner or later will be monetized in one way or another.